deshrimp — Sit straight shrimp

This page takes one picture from your webcam every second and reads three angles off it: how far your head sits in front of your shoulders, how far your shoulder line is off level, and how far your head is tilted sideways. The first one matters most — a neck carried too far forward is the reason this page exists. If any of them goes past your limit, it makes a noise, on every single crooked reading. The computing happens here in the browser: a pose model finds 33 points on your body and the page works out the angles itself. No key, no quota, and no picture leaving this device — the readings stay in this browser too.

1 · Start it

Allow the camera and leave the page open. There is nothing to set up and nothing to calibrate: all three angles are ratios measured on your own body, so they do not depend on how tall you are and read the same for anyone. The page measures from the very first frame and keeps the screen awake while it checks.

2 · Pick the pace

One picture a second by default, stretchable to two minutes. Because everything is computed locally, a fast pace costs nothing but a little battery — there are no requests to count.

3 · Pick the sound

Five to choose from: fart, ahem, scream, knuckle crack and rimshot. The fart is the default — you will not miss it and it will not startle you. It plays on every single crooked reading, so at the default pace once a second until you sit up. These are real recordings, they ship inside the page, and nothing is downloaded.

4 · Trust the trend, not the degree

How far your head juts forward is estimated along depth — the least certain axis a single camera has. So a snapshot is soft and the trend is not. The bar strip shows the day, the curve below shows the days; three red bars in a row mean something, one red bar between green ones is a moment. Pictures with nobody in them do not count at all.

5 · Look again in two weeks

Whether anything is changing does not show in one afternoon. At one picture a second a working day is tens of thousands of readings, so the individual ones are cleared after two days — the daily row from them is kept forever. The comparison „last 7 days against the 7 before“ is the real answer to „am I getting better“.

Sources

MediaPipe — Pose Landmarker — Google's documentation for the model that runs in this browser: 33 landmarks, each with a visibility score. The reason the angles here are computed rather than estimated.
Craniovertebral angle — Physiopedia — The one widely established cutoff for head posture: a craniovertebral angle below 48–50° counts as forward head posture. It is measured from C7 to the tragus in a side view — which is why this page cannot measure it, and does not pretend to.
Risk factors for neck pain in office workers: a prospective study — A prospective study of neck pain in office workers. The risk factors are duration and static loading, not any single angle — the reason this page emphasises the trend across days.
Effect of static neck flexion in cervical flexion-relaxation phenomenon — Ten minutes of sustained neck flexion already changes proprioception and muscle recruitment measurably. Evidence that held deviation is the problem, not the single crooked moment.
MDN — MediaDevices.getUserMedia() — The browser interface the page uses to reach the camera, including the rule that it only works in a secure context. That is why the app works over https but not from a file opened locally.
RxDB — die lokale Datenbank dieser Seite — Everything the page remembers lives in RxDB on IndexedDB — on this device, live across tabs, and still there after a reload. No server is involved.
BAuA — Steh-Sitz-Dynamik — The German federal institute for occupational safety on alternating between sitting and standing. The point that justifies this app at all: no single correct posture matters as much as changing it regularly.